The'purpose of the Histopathology Facility (HF) is to facilitate research conducted by funded investigators at Fox Chase Cancer Center (FCCC) by providing histology and pathology services including processing of cells and tissues as well as helping in the interpretation of results. The Facility's Technicians and Pathologist play a major support role in numerous research projects at the Center and their contributions have been, and continue to be of great significance in the establishment and characterization of animal models of human cancer. The Facility prepares, processes, and assists in evaluating tissues derived from experimental protocols developed by peer-reviewed, funded investigators. Most of the projects involve animal models of human cancer that require complex histological and/or cytological processing to determine morphological alterations, as well as to localize cancer-relevant gene products. The most frequently utilized services of the Facility during 2005-2009 include: laboratory animal autopsy, fixation, embedding and sectioning of paraffin-embedded tissue blocks (8,000-12,000 per year), unstained paraffin sections for immunohistochemistry (IHC) and laser capture microdissection (LCM) (9,000-14,000 per year), cryomicrotomy (200-1,500 per year), special stains (200-500 per year), immunohistochemistry (IHC) (2,100-3,700 per year), digital microphotography (3,000-5,000 per year), and interpretative histopathology (7,000- 10,000 H&E and IHC slides signed-out per year). During the last CCSG funding cycle we have seen a steady need for all services rendered and significant increase (100%) in the number of frozen sections performed. Furthermore, during 2005-2010 we consolidated new technology such as the web-based Experimental Histopathology database and introduced computerized image analysis. The HF also provides support to the Laboratory Animal Facility (LAF) in quality control and animal health monitoring activities, as well as processing support to the Biosample Repository Facility (BRF) and the LCM component of the Genomics Facility (GF). The HF was used by 39 peer-reviewed, funded investigators in all five Research Programs at FCCC, in calendar year 2009.